What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Are you referring to this form: https://www.jotform.com/62837945120155?
I checked that form and it looks like you currently have a Purchase Order payment integration in the form. This is why you are receiving the message that you "have already integrated a payment system".
If you want to use Paypal as the method of payment, you will have to delete the Purchase Order payment integration and replace it with the Paypal payment integration. You can follow the screen recording below:
You can also follow this guide for more information about the Paypal payment integration: PayPal Forms. Cheers.